Develop Reference

Searchable Dropdown with Flutter Rest Api Problem

I am Calling an Api to filter Countries list with Region. Whenever I Select the region it filter and show all countries of the selected region. I'm using searchable_dropdown package to filter.
My Searchable Dropdown Filter is Working Fine But Not getting All Data Without Selecting from Dropdown.
What i want :- i want to show all Available data from api when app runs or when no region is selected from dropdown as in Screenshot 1.
My Codes are Below
Main.dart
import 'package:flutter/material.dart';
import 'package:searchable_dropdown_flutter/searchable_dropdown1.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
// This widget is the root of your application.
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: SearchableDropdownApp(),
);
}
}
searchable_dropdown.dart
import 'package:flutter/material.dart';
import 'package:searchable_dropdown/searchable_dropdown.dart';
import 'dart:async';
import 'dart:convert';
import 'package:http/http.dart' as http;
class SearchableDropdownApp extends StatefulWidget {
#override
_AppState createState() => _AppState();
}
class _AppState extends State<SearchableDropdownApp> {
Map<String, String> selectedValueMap = Map();
// ignore: deprecated_member_use
List filteredData = List();
// ignore: deprecated_member_use
List filteredDataAll = List();
// ignore: deprecated_member_use
List alldata = List();
#override
void initState() {
selectedValueMap["server"] = null;
super.initState();
}
#override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(
automaticallyImplyLeading: false,
title: const Text('Searchable Dropdown Example App'),
),
body: FutureBuilder(
// get data from server and return a list of mapped 'name' fields
future:
getServerData(), //sets getServerData method as the expected Future
// ignore: missing_return
builder: (context, snapshot) {
if (snapshot.hasData) {
// ignore: deprecated_member_use
List<String> countries = new List();
for (int i = 0; i < snapshot.data.length; i++) {
if (!countries.contains(snapshot.data[i]['region']))
countries.add(snapshot.data[i]['region']);
}
alldata = snapshot.data;
//checks if response returned valid data
// use mapped 'name' fields for providing options and store selected value to the key "server"
return getSearchableDropdown(countries, "server", alldata);
} else if (snapshot.hasError) {
//checks if the response threw error
return Text("${snapshot.error}");
}
return Center(child: CircularProgressIndicator());
},
),
),
);
}
Widget getSearchableDropdown(List<String> listData, mapKey, alldata) {
List<DropdownMenuItem> items = [];
for (int i = 0; i < listData.length; i++) {
items.add(new DropdownMenuItem(
child: new Text(
listData[i],
),
value: listData[i],
));
}
return Scaffold(
body: Column(
children: [
SearchableDropdown(
isExpanded: true,
style: TextStyle(color: Colors.red),
items: items,
value: selectedValueMap[mapKey],
isCaseSensitiveSearch: false,
hint: new Text('Select Country'),
searchHint: new Text(
'Select Country',
style: new TextStyle(fontSize: 20),
),
onChanged: (value) {
setState(() {
selectedValueMap[mapKey] = value;
print('selectedValueMap[mapKey]');
print(selectedValueMap[mapKey]);
// ignore: deprecated_member_use
filteredData = new List();
for (int i = 0; i < alldata.length; i++) {
if (alldata[i]['region'] == selectedValueMap[mapKey])
filteredData.add(alldata[i]);
}
filteredDataAll = filteredData.toList();
print('filteredDataAll ka data');
});
},
),
Text(selectedValueMap[mapKey].toString()),
Text('data'),
Expanded(
child: Padding(
padding: const EdgeInsets.all(8.0),
child: ListView.builder(
scrollDirection: Axis.vertical,
shrinkWrap: true,
itemCount: filteredDataAll.length,
itemBuilder: (context, index) {
return SingleChildScrollView(
child: Card(
child: Padding(
padding: const EdgeInsets.all(8.0),
child: Column(
children: [
Text(filteredDataAll[index].toString()),
],
),
)),
);
}),
),
),
],
),
);
}
Future<List> getServerData() async {
String url =
'https://restcountries.eu/rest/v2/all?fields=name;capital;alpha3Code;region;population;';
final response =
await http.get(url, headers: {"Accept": "application/json"});
if (response.statusCode == 200) {
List<dynamic> responseBody = json.decode(response.body);
return responseBody;
} else {
print("error from server : $response");
throw Exception('Failed to load post');
}
}
}
SecreenShots
When App Run for First Time
SecreenShots 1
After Selecting from Filter
SecreenShots 2

try this its works fine for me...
FutureBuilder<List<AllAccountModel>>(
future: accountData,
builder: (context, snapshot){
if(snapshot.hasData){
List<String> dropDown=List.filled(snapshot.data!.length, '',growable: true);
print(snapshot.data!.length);
for(int i=0;i<=snapshot.data!.length-1;i++){
dropDown[i]=snapshot.data![i].accountName+"\n"+snapshot.data![i].phoneNo;
}
return DropdownSearch<String>(
mode: Mode.MENU,
items: dropDown,
showSearchBox: true,
label: "Account Name",
onChanged: print,
);
}else{
DropdownSearch<String>(
mode: Mode.MENU,
items: [snapshot.error.toString()],
showSearchBox: true,
label: "Account Name",
onChanged: print,
);
}
return
const Padding(
padding: EdgeInsets.all(8.0),
child: Center(
child:
CircularProgressIndicator(),
),
);
})
call Api in initState
#override void initState() {
// TODO: implement initState
super.initState();
accountData = allAccounts();}
my Api Function
Future<List<AllAccountModel>> allAccounts() async {
return HttpService().getAllAccounts();}
End Result

Information from api doesn't show - Flutter

I have a problem with Future builder in Flutter. It gets the info from api successfully but doesn't show it. When I put print and print the info from api, it is ok and it shows the movies name without any problems. here is my code:
class Search extends StatefulWidget {
final String value;
Search({Key key, String this.value}) : super(key: key);
#override
_SearchState createState() => _SearchState();
}
class _SearchState extends State<Search> {
var title;
Future getSearch({index}) async {
http.Response response = await http.get(
'https://api.themoviedb.org/3/search/company?api_key=6d6f3a650f56fd6b3347428018a20a73&query=' +
widget.value);
var results = json.decode(response.body);
setState(() {
this.title = results['results'];
});
return title[index]['name'];
}
getName(index) {
return title[index]['name'];
}
#override
Widget build(BuildContext context) {
return SafeArea(
child: Scaffold(
backgroundColor: Color(0xff1d1d27),
body: Column(
children: [
Expanded(
child: FutureBuilder(
initialData: [],
future: getSearch(),
builder: (context, snapshot) {
return ListView.builder(itemBuilder: (context, index) {
Padding(
padding:
EdgeInsets.symmetric(horizontal: 30, vertical: 20),
child: Container(
color: Colors.white,
child: Text(getName(index).toString()),
),
);
});
},
))
],
)),
);
}
}

Please Use this code, It works fine to fetch the names and show them on the list,
import 'dart:convert';
import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
class Search extends StatefulWidget {
final String value;
Search({Key key, String this.value}) : super(key: key);
#override
_SearchState createState() => _SearchState();
}
class _SearchState extends State<Search> {
var title;
var results;
getSearch() async {
http.Response response = await http.get(
'https://api.themoviedb.org/3/search/company?api_key=6d6f3a650f56fd6b3347428018a20a73&query=' +
widget.value);
results = json.decode(
response.body); //make it global variable to fetch it everywhere we need
return results['results'][0]['name'];
}
getName(index) {
return results['results'][index]['name'];
}
#override
Widget build(BuildContext context) {
return SafeArea(
child: Scaffold(
backgroundColor: Color(0xff1d1d27),
body: Column(
children: [
Expanded(
child: FutureBuilder(
// initialData: [],
future: getSearch(),
builder: (context, snapshot) {
String name =
snapshot.data; // to get the data from the getSearch
print(name);
if (snapshot.hasData) {
// if there is data then show the list
return ListView.builder(
itemCount: results['results']
?.length, // to get the list length of results
itemBuilder: (context, index) {
return Padding(
padding: EdgeInsets.symmetric(
horizontal: 30, vertical: 20),
child: Container(
color: Colors.white,
child: Text(getName(index)
.toString()), // pass the index in the getName to get the name
),
);
});
} else {
// if there is no data or data is not loaded then show the text loading...
return new Text("Loading...",
style: TextStyle(fontSize: 42, color: Colors.white));
}
},
))
],
)),
);
}
}
P.S
To Learn the basics of Futurebuilder You can see this article For more learning
I have commented the code to explain more to you.

Flutter : Provider do not update data in the previous screen

In my Flutter application I am using Provider version 4.0.4 to manage the state of my app. In basic terms, my app will list down the nearby companies with their rating. users can select a organisation, open it and add their rating as well, so the final rating will be updated. I am using the Consumer concept in Provider to handle the tasks.
In NearByPlacesPage class I am listing down the companies around me with rating information. User can click on a company and they will be taken to OrganizationPage page.
In OrganizationPage class, the rating is displayed again. user can add their rating to the system. Then the rating information in both OrganizationPage page and NearByPlacesPage (back page) need to be updated.
The issue is, when the user update the rating, the rating in OrganizationPage get updated but not NearByPlacesPage in back stack. When we go back to NearByPlacesPage, we can clearly see the old rating values. The page need to be reloaded to get updated values.
Below are the important sections in my code
NearByPlacesPage
class NearByPlacesPage extends StatelessWidget {
int orgTypeID;
String orgTypeName;
NearByPlacesPage(this.orgTypeID, this.orgTypeName);
#override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.white,
body: MultiProvider(
providers: [
ChangeNotifierProvider(create: (context) => RatingService()),
],
child: SingleChildScrollView(
child: _NearByPlacesPageUI(orgTypeID, orgTypeName),
),
),
appBar: AppBar(
title: Text(orgTypeName),
),
);
}
}
class _NearByPlacesPageUI extends StatefulWidget {
int orgTypeID;
String orgTypename;
_NearByPlacesPageUI(this.orgTypeID, this.orgTypename);
#override
State<StatefulWidget> createState() {
return _NearByPlacesPageState();
}
}
class _NearByPlacesPageState extends State<_NearByPlacesPageUI> {
#override
Widget build(BuildContext context) {
Consumer<RatingService>(builder: (context, data, child){
return Flexible(
child: ListView.builder(
itemCount: orgList.length,
itemBuilder:(BuildContext context, int index) {
Organization organization = orgList[index];
if (organization.isDisabled != true) {
RatingValue ratingValue = data.getData();
return Container(
margin: EdgeInsets.only(
top: 5, left: 5, right: 5),
child: _buildPlace(organization, ratingValue));
} else {
return Container();
}
},),
);
},);
}
}
OrganizationPage
class OrganizationPage extends StatelessWidget {
Organization organization;
String orgTypeName;
OrganizationPage(this.organization, this.orgTypeName);
#override
Widget build(BuildContext context) {
return Scaffold(
body: SingleChildScrollView(
child: _OrganizationPageUI(organization, orgTypeName),
),
backgroundColor: Colors.white,
appBar: AppBar(
title: Text(organization.name),
),
);
}
}
class _OrganizationPageUI extends StatefulWidget {
Organization organization;
String orgTypeName;
_OrganizationPageUI(this.organization, this.orgTypeName);
#override
State<StatefulWidget> createState() {
return _OrganizationPageState();
}
}
class _OrganizationPageState extends State<_OrganizationPageUI> {
#override
Widget build(BuildContext context) {
Consumer<RatingService>(
builder: (context, data, child) {
Consumer<RatingService>(
return Row(
children: <Widget>[
Container(
margin: EdgeInsets.only(top: 10, left: 10),
child: Text(daa.getData()
style: Theme.of(context).textTheme.bodyText2.apply(color: Colors.grey),
),
),
],
);
),
}
}
}
In OrganizationPage there is a AlerDialog, which allows the user to rate and save. When saved, it will call another method which will reload the data.
Widget _ratingDialog(double _rating) {
RatingService _ratingService =
Provider.of<RatingService>(context, listen: false);
Rating _rating = _ratingService.returnRating();
double _ratingValue = _ratingService.returnRating().rating;
return AlertDialog(
title: const Text("Your Rating"),
actions: [
new FlatButton(
child: const Text("Save"),
//onPressed: () => Navigator.pop(context),
onPressed: () async {
Rating rating = Rating(
idrating:
_rating.idrating != null ? _rating.idrating : null,
user: _user,
organization: widget.organization,
rating: _ratingValue,
dateCreated: DateTime.now().millisecondsSinceEpoch,
lastUpdated: DateTime.now().millisecondsSinceEpoch);
await _ratingService.saveOrUpdateRating(rating, authToken);
_loadRatingByUserAndOrganization(authToken);
_loadRatingValueByOrganization(authToken);
Navigator.pop(context);
},
),
],
);
}
Future _loadRatingByUserAndOrganization(String authToken) {
RatingService _ratingService =Provider.of<RatingService>(context, listen: false);
return _ratingService.getRatingByUserAndOrganization(
_authService.getDatabaseUser().user.iduser,
widget.organization.idorganization,
authToken);
}
RatingService
This is the class which is responsible for calling notifyListeners(). It will be triggered by the above AlertDialog and the expected behaviour is to reload data in both OrganizationPage and NearByPlacesPage
class RatingService with ChangeNotifier {
List<RatingValue> _ratingValueList ;
List<RatingValue> getData()
{
return _ratingValueList;
}
//Load rating by user and Organization
Future<void> getRatingByUserAndOrganization(int idUser, int organizationID, String authToken) async {
try {
var data = await http.get(
_navLinks.getRatingByUserAndOrganization(idUser, organizationID),
headers: {HttpHeaders.authorizationHeader: "Bearer $authToken"},
);
print(data.body);
_rating = Rating.fromJson(convert.json.decode(data.body));
notifyListeners();
} catch (error) {
print(error);
throw error;
}
}
}
What I have I done wrong?

Flutter- Make the app show the previously fetched data when device is offline

I'm new to Flutter and need a bit of help. I've built a random joke generator app that reads data from the API and displays a new joke every time a button is pressed. I want to make the app show the previously fetched data when device is offline. I tried searching online but found nothing that does it using Flutter.
class _HomePageState extends State<HomePage> {
List data;
Future<Jokes> post;
String url="https://official-joke-api.appspot.com/random_joke";
var response;
Future<Jokes> getData() async {
response =
await http.get(url, headers: {"Accept": "application/json"});
if (response.statusCode == 200) {
return Jokes.fromJson(json.decode(response.body));
} else {
throw Exception('Failed to load post');
}
}
changeApi()
{
setState(() {
if (response.statusCode == 200) {
return Jokes.fromJson(json.decode(response.body));
} else {
throw Exception('Failed to load post');
}
});
}
#override
void initState()
{
super.initState();
this.getData();
}
#override
Widget build(BuildContext context) {
final key = new GlobalKey<ScaffoldState>();
// TODO: implement build
return Scaffold(
key: key,
backgroundColor: Colors.amberAccent,
body: new Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
new FutureBuilder<Jokes>(
future:
getData(),
builder: (context, snapshot) {
if (snapshot.hasData) {
//checks if the response returns valid data
return Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
new GestureDetector(
child: new Text(
snapshot.data.setup ,
style: TextStyle(fontFamily: "Rock Salt"),
),
onLongPress: ()
{
Clipboard.setData(new ClipboardData(text: snapshot.data.setup, ));
key.currentState.showSnackBar(
new SnackBar(content: new Text("Copied to Clipboard"),));
},
),
/
SizedBox(
height: 10.0,
),
new GestureDetector(
child: new Text(
" - ${snapshot.data.punchline}",
style: TextStyle(fontFamily: "Roboto"),
),
onLongPress: ()
{
Clipboard.setData(new ClipboardData(text: snapshot.data.punchline));
key.currentState.showSnackBar(
new SnackBar(content: new Text("Copied to Clipboard"),));
},
),
],
),
);
} else if (snapshot.hasError) {
//checks if the response throws an error
return Text("${snapshot.error}");
}
return CircularProgressIndicator();
},
),
SizedBox(
height: 25.0,
),
new RaisedButton(
onPressed: changeApi,
color: Colors.pinkAccent,
child: Text("Press for a new joke", style: TextStyle(color: Colors.white,)),
)
],
),
),
);
}
}
class Jokes {
final String setup;
final String punchline;
Jokes({this.setup, this.punchline});
factory Jokes.fromJson(Map<String, dynamic> json) {
return Jokes(setup: json['setup'], punchline: json['punchline']);
}
}
Api
Here's my full code: code

There are some videos about caching, here's the one from flutter team, and one from tensor programming channel.
You can use connectivity plugin to check whether the device is offline.
If device is offline, show data from shared_preferences or sqflite, if it's online, fetch new data (and of course update your cache).

Manage state of one page from another class

I'm building an app for training in Flutter and I'm actually stuck in the filter functionality.
I have a ListView where I fetch data from TheMovieDB API and a ModalBottomSheet with three FilterChips for selecting the filter criteria (popular, top rated and latest movies).
And here's where I'm stuck. I want to call the "_loadNextPage()" method when the user presses the "Done" button in the ModalBottomSheet through "performUpdate()" but I can't do it because they're not in the same class.
I'll post the code down below for better understanding.
class _HomePageState extends State<HomePage> {
RequestProvider _requestProvider = new RequestProvider();
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("FluttieDB"),
actions: <Widget>[
IconButton(
icon: Icon(Icons.filter_list),
onPressed: () => buildFilterBottomSheet(),
)
],
),
body: MovieList(_requestProvider, _currentFilter),
);
}
void buildFilterBottomSheet() {
showModalBottomSheet(
context: context,
builder: (builder) {
return Container(
height: 150.0,
decoration: BoxDecoration(color: Colors.white),
child: Column(
children: <Widget>[
buildFilterTitle(context),
Expanded(
child: _FilterChipRow(),
),
],
),
);
});
}
Widget buildFilterTitle(BuildContext context) {
return Container(
padding: const EdgeInsets.symmetric(horizontal: 12.0, vertical: 6.0),
alignment: Alignment.centerLeft,
height: 46.0,
decoration: BoxDecoration(color: Colors.blue),
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
mainAxisSize: MainAxisSize.max,
children: <Widget>[
Text(
"Filter by",
style: TextStyle(color: Colors.white, fontSize: 20.0),
),
OutlineButton(
onPressed: () => performUpdate(context),
padding: const EdgeInsets.all(0.0),
shape: const StadiumBorder(),
child: Text(
"Done",
style: TextStyle(color: Colors.white),
),
),
],
),
);
}
void performUpdate(BuildContext context) {
MovieList _movieList = new MovieList(_requestProvider, _currentFilter);
_movieList.createState()._loadNextPage();
Navigator.pop(context);
}
}
class MovieList extends StatefulWidget {
MovieList(this.provider, this.currentFilter, {Key key}) : super(key: key);
final RequestProvider provider;
final String currentFilter;
#override
_MovieListState createState() => new _MovieListState();
}
class _MovieListState extends State<MovieList> {
List<Movie> _movies = List();
int _pageNumber = 1;
LoadingState _loadingState = LoadingState.LOADING;
bool _isLoading = false;
_loadNextPage() async {
_isLoading = true;
try {
var nextMovies = await widget.provider
.provideMedia(widget.currentFilter, page: _pageNumber);
setState(() {
_loadingState = LoadingState.DONE;
_movies.addAll(nextMovies);
_isLoading = false;
_pageNumber++;
});
} catch (e) {
_isLoading = false;
if (_loadingState == LoadingState.LOADING) {
setState(() => _loadingState = LoadingState.ERROR);
}
}
}
#override
void initState() {
super.initState();
_loadNextPage();
}
#override
Widget build(BuildContext context) {
switch (_loadingState) {
case LoadingState.DONE:
return ListView.builder(
itemCount: _movies.length,
itemBuilder: (BuildContext context, int index) {
if (!_isLoading && index > (_movies.length * 0.7)) {
_loadNextPage();
}
return MovieListItem(_movies[index]);
});
case LoadingState.ERROR:
return Center(
child: Text("Error retrieving movies, check your connection"));
case LoadingState.LOADING:
return Center(child: CircularProgressIndicator());
default:
return Container();
}
}
}
As you can see, I did some experiments in the performUpdate() but it doesn't refresh the ListView with the selected option in the filters and I don't think it's the best way to achieve what I want.
Thanks and sorry if the question is a bit dumb. I'm a little bit newbie in Flutter.

Redux is a great state management library that originated with React and JS, but has been ported to Dart, and has a flutter specific library as well. Redux is a very powerful framework which uses a pub/sub system to allow your view to subscribe to changes to the model, while using a system of "actions" and "reducers" to update the model.
A great tutorial for getting up and running with Redux in Flutter can be found here
Alternatively you could look into the scoped model, which is another state management library for flutter. The scoped model is less capable, but for simple use cases may be more than adequate.
Further reading:
Understand and choose a state management solution
You Might Not Need Redux